ThePog Posted April 10, 2011 Author Share Posted April 10, 2011 So I have a bike geometry q for all you knowledgeable kernts out there.... Longbike, while superior in nearly every aspect of performance/load carrying ability/awesome etc, has a handling issue in that you simply cannot let go of the bars in an upright position without the fuckers darting to one side and making you poo your pants a little bit. It is actually not enough of a problem to make me not ride it, but it would be good too see if this can be improved. Having pondered the issue during the many miles I have now covered on this beast I have decide that it is either about the angle of the steering pivot line or the distance between the steering pivot line and the front axle. So what I want to know is this; which is the most likely culprit so I can make this better? Thanks in advance. Quote Link to comment Share on other sites More sharing options...
DodgySam Posted April 10, 2011 Share Posted April 10, 2011 If you change the forks to straight forks it will improve this greatly. I believe the issue you are having is due to the rake of the front end. you could cut and weld the head tube etc but try the easy way first and just get rid of the curved forks as they are moving the wheel forward about 2+inches. Try it...what could possibly go wrong? Quote Link to comment Share on other sites More sharing options...
EURON8 Posted April 10, 2011 Share Posted April 10, 2011 If you change the forks to straight forks it will improve this greatly.I believe the issue you are having is due to the rake of the front end. you could cut and weld the head tube etc but try the easy way first and just get rid of the curved forks as they are moving the wheel forward about 2+inches. Try it...what could possibly go wrong? Seems odd as the bike geometery hasnt changed in terms of angles, just length. the steering angle is still the same as before is it not? Appears so lookig at side on pics Quote Link to comment Share on other sites More sharing options...
DodgySam Posted April 10, 2011 Share Posted April 10, 2011 I think u'll find in removing the rear triangle/chainstays the rear end has lowered slightly therefore increasing the angle of rake. Quote Link to comment Share on other sites More sharing options...
ThePog Posted April 10, 2011 Author Share Posted April 10, 2011 I found this, which sort of makes sense; http://www.dclxvi.org/chunk/tech/trail/ I would have thought the rake would need to be increased, not decreased, but straight forks would increase the trail in this case. I have found most mountainbikes are twitchy in this respect, it is usually pretty hard to ride them with no hands, but my old 10 speed based single speed is totally bulletproof for no hands... and that looks like it has more rake and a lot of wheel to stem offset.. Longbike is based on an old MB, obviously enough has changed in the geometry to effectively reduce the trail or at least make the amount of trail (or lack) more noticeable. So I can either try straight forks or more rake? Quote Link to comment Share on other sites More sharing options...
ThePog Posted April 13, 2011 Author Share Posted April 13, 2011 Treated longbike to a new set of handlebars + quill stem adaptor + adjustable stem, it is like riding an armchair now... I tried swapping the seat for an old sprung one that I had lying around, unfortunately it isn't in top condition and it felt like someone was banging a nail into your perineum, so I swapped back the old one. I have decided to put 700C rims on it for extra largeness - does anyone have a spare set lying around that I could purchase? I chucked on the ones from my other bike which mostly fitted, I will need to move the brake mounts and/or buy a different fork for it. Quote Link to comment Share on other sites More sharing options...
ThePog Posted May 4, 2011 Author Share Posted May 4, 2011 Got a very wet arse on the run home Monday evening, decided that mudguards were probably the ticket so got these real steel bad boys from Velo Ideale for $40, I kind of like the rust vs very shiny thing going on; Also took off the new bars etc as it all looked way too technical and serious, but I needed a very long stem so I could use a spare set of Raleigh bars I had, behold the roughness; Perfect riding position tho In other news, I purchased these two Sram P5 internal gear hubs off TM, no idea of completeness or condition but shit they were cheap; IGH goodness will follow shortly. Quote Link to comment Share on other sites More sharing options...
Steelies Posted May 4, 2011 Share Posted May 4, 2011 score on the hubs! all i can picture is carrying a 1/2 length of pvc conduit with a rag on the back.. Quote Link to comment Share on other sites More sharing options...
ThePog Posted May 4, 2011 Author Share Posted May 4, 2011 yea I welded a couple of extra supports at the front for this exact situation, must make an excuse to plumb some shit Quote Link to comment Share on other sites More sharing options...
ThePog Posted May 14, 2011 Author Share Posted May 14, 2011 Stripped the hubs, one is ok, one is fucked. I found some cash so decided to just buy a new hub anyway and use the good secondhand one in something else so this is todays effort; Shifter cable is too short bit I will sort that later. Otherwise it is mint, can hit warp factor 9 no probs now. Quote Link to comment Share on other sites More sharing options...
felixx Posted June 2, 2011 Share Posted June 2, 2011 Looooooooooongbike is superb! I bow down in front of your greatness! Quote Link to comment Share on other sites More sharing options...
~Leroy~ Posted June 2, 2011 Share Posted June 2, 2011 A haters gunna hate sticker seems fitting i must say Quote Link to comment Share on other sites More sharing options...
ThePog Posted June 3, 2011 Author Share Posted June 3, 2011 Ha, now that the daily commute on this has my thighs looking like fucking tree trunks I tend to see all but the most serious lycra boys as an easily attainable challenge - I passed one a couple of days who was sitting on about 25km/hr - I was cranking at a large fraction of light speed (37km/hr), it must have seemed like being passed by a fucking freight train. It must be depressing to be totally ruled by something so stupid and massive riding such a ridiculous looking bike... Quote Link to comment Share on other sites More sharing options...
Jase Posted June 3, 2011 Share Posted June 3, 2011 ^qft they get iffy when you pace past them on a single speed also, must get me one of those hubs and some guards for 700c Quote Link to comment Share on other sites More sharing options...
ThePog Posted June 3, 2011 Author Share Posted June 3, 2011 yea I have a normal bike with derailleurs etc, but I swear I can go faster on longbike for a given situation - those hubs have a high mechanical efficiency compared to a normal setup, something like 90-95% transmission efficiency depending on the gear you are in. Also BTW I saw 45km/hr coming down Wigram road today - a new longbike personal best.... Quote Link to comment Share on other sites More sharing options...
ThePog Posted June 5, 2011 Author Share Posted June 5, 2011 Painted longbike this weekend.... Looks nice from far/far from nice, the rust converter I put on made life difficult. Plus it is a little lighter than I wanted. Still it achieves a level of civility that it lacked before. I also brought an old Brooks B66 which looked sweet on it but made my hammies go spastic, so swapped back the old one. I might try and find a skinnier one... I nearly died the other day on the way to work through lack of stopping power, so I dropped by the cycle shop and purchased some sidepull MTB brakes so it could stop properly, now it does. Also purchased a new long stem - should be here tuesday. Also made up a longer shift cable, this meant I could route it properly. Also looking for proper cranks - giz. That is all. Quote Link to comment Share on other sites More sharing options...
felixx Posted June 21, 2011 Share Posted June 21, 2011 Just realised you are in chch! If you ever want to sell her.. let me know Quote Link to comment Share on other sites More sharing options...
xsspeed Posted June 21, 2011 Share Posted June 21, 2011 Your cranks should already be three piece? If so, a) you may be able to undo one of the drive rings - leaving you with one (sometime this doesn't leave you with the one you want though, ie 40T instead of 50T or vice versa) undo all, the drive side crank arm should be bolted to the chain ring via a 5 stud arrangement - find what the PCD is and order a chain ring in the size you want with that pcd - can often find them for sale on trademe too. Sorry if thats teaching you to suck eggs, assume thats the info you were after though? Quote Link to comment Share on other sites More sharing options...
anglia4 Posted June 22, 2011 Share Posted June 22, 2011 Man I love this thing Quote Link to comment Share on other sites More sharing options...
ThePog Posted June 22, 2011 Author Share Posted June 22, 2011 Na crankrings are shitty pressed steel jobbies, flex like fuck and spot welded/rivetted together. I found what I wanted on TM last night anyway, shimano bolting type cranks for $20, also have already bought a 48 tooth sprocket altho this is one of the spastic biopace ones, will have to see how that works out... Just realised you are in chch! If you ever want to sell her.. let me know I have been thinking about a MKII version which will incorporate many improvements + be made properly rather than thrown together. If this happens then this one might be surplus to requirements. It owes me an unfortunate amount of money tho, so start saving now. Quote Link to comment Share on other sites More sharing options...
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